To ensure maximum utility of the Imaging Core, we will combine the strengths ofnon-invasive magnetic resonance (MR) and positron emission tomography (PET) imaging techniques essential to this SCOR application. At the macroscopic whole animal level, we will utilize new small animal imaging technologies, including MRI, microPET, and microCAT. The primary roles of the Imaging Core will be to: monitor the number of mouse embryos present in pregnancy and measure the size of the embryo and placenta using MRI; perform longitudinal MRI studies of pregnant monkeys and monitor viability and phenotypic differences of the fetus and placenta throughout pregnancy; employ high-resolution 3D MRI of fixed mouse embryos to examine smoking-induced skeletal and vascular alterations; employ non-invasive monitoring of normal pregnancy in non-human primates utilizing PET imaging and glucose and amino acid tracers; delineate paternal vs. maternal contributions in adrogenotes and gynogenotes using reporter gone techniques; to monitor leukocytes invasion and inflammatory response related to the progression of physiologic and pathologic labor and evaluate the effects of smoking on the transport of glucose and amino acids across the placenta. The functions of the Imaging Core will be performed at two locations: MRI methods will be performed at the Pittsburgh NMR Center, Carnegie Mellon University and microPET/microCAT imaging studies will be performed at the UPMC PET Facility, University of Pittsburgh. Both of these facilities are designed for the purpose of providing state of the art non-invasive imaging technologies to biomedical researchers. The MRI component of the Imaging Core will provide a vital resource to the proposed Projects. Projects 1 and 2 will longitudinally follow pregnancies in mouse and in monkey. From these time-lapse data the viability and phenotypic differences of the fetus and placenta will be monitored throughout pregnancy. In Project 3, novel 3D microangiography methods will be utilized to globally examine the impact of smoking on the vascularization of the developing fetus. For the mouse studies, specialized MRI capabilities will be used called magnetic resonance microscopy (MRM); this is an emerging technique capable of imaging biological subjects in vitro and in vivo at nearcellular resolution. MRI will help bridge the gap between pregnancy models in mouse and in primates. The Pittsburgh NMR Center has state-of-the art in vivo imaging capabilities for both model systems.